Method of making heat exchangers



A rifl 2, 1942.

c. STEENSTRUP 2,281,299

METHOD OF MAKING HEAT EXCHANGERS Filed Aug. 14, 1941 Q Q J Inveh-bor Chri stiah Stenscrup b y Hi Attorney.

Patented Apr. 28, 1942 METHOD OF MAKING HEAT EXCHANGERS Christian Steenstrup, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application August 14, 1941, Serial No. 406,753

4 Claims.

This invention relates to heat exchange apparatus and more particularly to a method for making a heat exchange tube and fin therefor.

It is an object of my invention to provide a new and improved method for forming a heat exchange tube and fin therefor which is relatively simple and inexpensive to manufacture but which is rugged in construction and efiicient in operation.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had'to the accompanying drawing in which Fig. 1 is a perspective view of a completed heat exchange conduit and fin therefor; Fig, 2 is a perspective view illustrating the tube and fin at one stage of manufacture; and Figs. 3 and 4 illustrate apparatus for performing the steps of assembling the device shown in Fig. 1.

In the formation of a heat exchange element,

such as illustrated in Fig. 1 of the drawing, a

sheet 10 of metal of relatively good heat .conducting characteristics is formed with a longitudinally extending groove I I. In this groove may be interposed a pre-formed tube l2 of heat conductive material for conducting a fluid through a .3

heat exchanger. Any suitably pre-formed section of tubing may be employed but I prefer to utilize tubing having an open seam l3, with the open seam disposed in the bottom of the groove as shown in the drawing. After thus positioning the tube in the groove, the sheet In is acted upon to force the material about the tubeto the position shown in Fig. 1, thereby providing fins l4 and closing the seam I3. As a final step in the assembly process the sheet and tube members are suitably secured to each other, preferably by brazing.

In order to cause the sheet In to assume the final position shown in Fig. 1, I form the longitudinally extending sheet 10 not only with the longitudinally extending groove II and I also bend the wing or fin portions, on'either side of the groove II, to form longitudinally extending upstanding ridges or corrugations 15. If the edges of the strip are then confined against outward lateral movement, the upstanding walls I6 of the groove and the adjacent fin portions will be forced inwardly around the periphery of the tube by any flattening force on the bent wings or fins. In this manner, I provide a double-walled tube having intimate thermal engagement between the walls and which is fluid-tight, the brazing action improving the heat exchange relationship and further rendering the tube fluid-tight.

In order to flatten out the fin portions and to cause the seam to be closed and the tube to be enveloped in the strip Ill, I have provided complementary shaping or forming members, as die members I! and Ill. The former is provided'with a recess I 9 having a longitudinally extending groove 20 to receive the grooved portion ll of the sheet Ill. The walls 2| defining the recess l9 serve to confine the edges of the fins against outward lateral movement during the time in which the die member I8 is being forced downwardly into the recess l9 for flattening the fins and forcing the sheet around the tube l2.

While I have shown a particular embodiment of my invention, modifications will occur to those skilled in the art. For example, any suitable means may be used for flattening the sheet l0. Thus, cooperating rolls may be used. Moreover, a plurality of passages may be provided in a single sheet instead of the one shown. While it is desirable to provide a corrugation on each side of each groove ll, substantial benefits will be obtained with a corrugation on only one side. Therefore, I do not desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The method of forming a heat exchange element comprising the steps of forming a sheet of relatively good heat conducting material with a longitudinally extending groove, bending said sheet to form a longitudinally extending upstanding ridge or corrugation on each side of said groove, interposing a pre-formed section of tubing in said groove, and acting on said sheet to flatten out said ridge portion of said sheet and to force said sheet around the tube while confining the edges of said sheet against outward lateral movement.

2. The method of forming a heat exchange element comprising the steps of forming a sheet of relatively good heat conducting material with a longitudinally extending groove, bending said sheet to form a longitudinally extending upstanding ridge or corrugation, interposing a preformed section of tubing in said groove, and acting on said sheet to flatten out said ridged portion of said sheet and to force said sheet around the tube while confining the edges of said sheet against outward lateral movement.

3. The method of forming a heat exchange element comprising the steps oi forming a sheet of relatively good heat conducting material with a longitudinally extending groove, bending said sheet to form a longitudinally extending upstanding ridge or corrugation, interposins a Preformed section of tubing in said groove, acting on said sheet to flatten out said ridged portion and to force said sheet around the tube while confining the edges of said sheet against outward lateral movement, and providing a bond having good heat conducting characteristics between the tube and the sheet,

aasmaa 4. The method or forming a heat exchange element comprising the steps of forming a sheet of relatively good heat conducting material with a longitudinally extending groove, bending said sheet to iorm a longitudinally extending upstanding ridge or corrugation, providing openseamed tubing, interposing a section of said tubing in said groove with the open seam in the bottom of said groove, and acting on said sheet to flatten out said ridged portion of said sheet and to force said sheet around the tube while confining the edges of said sheet against outward lateral movement.

CHRISTIAN BTEENSTRUP. 

